Vacuum operated piezoelectric ignition means and actuator therefor



g- 4, 1970 A. GOOD 3,523,201

VACUUM OPERATED PIEZOELECTRIC IGNITION MEANS AND ACTUATOR THEREFOR Filed Ja n. is, 1968 2 Sheets--Sheet IOI 9 .52 I02 I28 I22 96 H6 509 Ill 7'' H2 77 83 I 79 H8 8O I /1 /II] [I I I l AI/IZ mvEmoR ARTHUR L. GOOD HlS ATTORNEYS 89 FIG.4

United States Patent 3 523 201 VACUUM OPERATEDPIEZOELEOTRIO IGNITION MEANs AND ACTUATOR THEREFOR Arthur L. Good, Elkhart, Ind., assignor to Robertshaw Controls Company, Richmond, Va., a corporation of Delaware Filed Jan. 15, 1968, Ser. No. 698,006 Int. Cl. H01v 7/00 US. Cl. 3108.7 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a pneumatically operated ignition means for burner means of a cooking apparatus or the like as well as to an improved pneumatically Operated actuator therefor or the like.

It is well known that many cooking apparatus of the fuel burning variety have individual pilot burner means for each main burner thereof whether the main burner is disposed in the oven or on top of the cooking apparatus, the pilot burners being continuously burning pilot burners and when adversely put out because of air current or the like, the same must be reignited by the housewife or the like utilizing matches and the like.

However, according to the teachings of the invention set forth in the copending patent application, Ser. No. 670,307, filed Sept. 25, 1967, and assigned to the same assignee to whom this application is assigned, ignition means are provided for such pilot burner means wherein the housewife or the like can initiate the actuation of the ignition means completely remote from the pilot burner means while igniting the pilot burner means in a simple andefiective manner.

' In particular, the ignition means of the afore-mentioned copending patent application includes piezoelectric crystal meansthat when actuated by the housewife or the like will have the stresses therein altered in such a manner that the same will cause sparking at the pilot burner means to ignite the same.

One feature of this invention is to provide improved means for causing the altering of the stresses in such crystal means or the like by utilizing a pneumatically operated actuator means.

In particular, the pneumatically operated actuator means of this invention is so constructed and arranged in a manner hereinafter illustrated and described that the same is adapted to automatically cycle itself between its deactuated position and its actuated position as long as the housewife or the like directs a pneumatic source to the actuator so that the cycling actuator will continuously cause the altering of stresses in the piezoelectric crystal means for the ignition sparking at the pilot burner means.

Accordingly, it is an object of this invention to provide an improved ignition means for a cooking apparatus or the like, the ignition means of this invention having one or more of the novel features set forth above or hereinafter shown or described.

Another object of this invention is to provide an improved pneumatically operated actuator for such an ignition means or the like.

Other objects, uses and advantages of this invention are apparent from a reading of this description which proceeds with reference to the accompanying drawings forming a part thereof and wherein:

FIG. 1 is a perspective view of the improved pneumatically operated actuator means of this invention.

FIG. 2 is an enlarged, schematic, cross-sectional view taken substantially on line 22 of FIG. 1 and illustrates the actuator of this invention for actuating a piezoelectric crystal ignition means for a cooking apparatus or the like.

FIG. 3 is a fragmentary view similar to FIG. 2 and illustrates the actuator as the actuator is ending its deactuated stroke.

FIG. 4 is a view similar to FIG. 3 and illustrates the actuator as the same is beginning its actuated stroke.

While the various features of this invention are hereinafter described and illustrated as being particularly adaptable for providing ignition means for a cooking apparatus, it is to be understood that the various features of this invention can be utilized singly or in any combination thereof to provide ignition means and/ or actuator means for other apparatus as desired.

Therefore, this invention is not to be limited to only the embodiment illustrated in the drawings, because the drawings are merely utilized to illustrate one of the wide variety of uses of this invention.

Referring now to FIG. 2, a cooking apparatus is generally indicated by the reference numeral 10 and has an oven chamber 11 provided with a broil burner 12 and a bake burner 13 illustrated in FIG. 2 as being in tubular form.

The cooking apparatus 10 includes a plurality of top burner means with only two top burner means 15 and 16 being illustrated schematically in FIG. 2.

Individual pilot burner means are provided for the main burners of the cooking apparatus 10 and the broil pilot burner is generally indicated by the reference numeral 19, the bake pilot burner by the reference numeral 20 and the top pilot burners are generally indicated by the reference numerals 21 and 22 for the respective top burners 15 and 16. The pilot burners 19, 20, 21 and 22 are illustrated schematically in FIG. 2 and are so constructed and arranged that the same are adapted to ignite fuel issuing from the respective main burner means 12, 13, 15 and 16 as long as the respective pilot burners are burning.

However, should one or more of the pilot burners of the cooking apparatus 10 be extinguished for any reason, spark igniting means of this invention is provided for the apparatus 10 and is generally indicated by the reference numeral 25 in FIG. 2 and will now be described.

The spark igniting means 25 comprises a support or frame member 26 suitably mounted to the frame structure 27 of the cooking apparatus 10 so that a manual actuator means 28 of the igniter means 25 will be exposed in any suitable location on the apparatus 10, the embodiment of the igniter means 25 illustrated in FIG. 2 having the manual actuator means 28 located on the conventional control panel means of the apparatus 10.

The support frame 26 has one or more piezoelectric crystal elements carried therein between the opposed ends 30 and 31 thereof with such crystal means being disposed in a recess or cutout 32 of the support frame 26. In the embodiment of the igniter means 25 illustrated in FIG. 2, two such piezoelectric crystal elements 33 and 34 are being utilized.

The crystal elements 33 and 34 are disposed in longitudinal stacked and aligned relation with the element 33 having electrical terminal means 35 and 36 at the opposed ends thereof and the crystal element 34 having electrical terminal means 37 and 38 at the opposed ends thereof. An electrical insulator 39 is disposed between the terminal means 36 and 37 of the crystal elements 33 and 34 to effectively electrically insulate the elements 33 and 34 from each other while electrical insulating means 40 and 41 respectively electrically insulate the other ends of the crystal elements 33 and 34 from the support frame 26 whereby the crystal elements 33 and 34 are not only electrically insulated from each other, but are also electrically insulated from the support frame 26 and, thus, from the frame means 27 of cooking apparatus 10. If desired, ceramic pressure pads or elements 42 and 43 can be respectively disposed between the insulators 40 and 41 and the respective terminal means 35 and 38 as illustrated.

A rocker arm 44 is pivotally or rotatably carried by the support frame 26 and is adapted to rotate relative thereto about a transversely movable axis of rotation generally indicated by the reference numeral 45, the rocker arm 44 carrying a cam member 46 at the rotatably mounted end 47 thereof to be disposed between the insulator 40 and a flat surface 48 of the support frame 26 at the end 30 thereof to also rotate in unison the rocker arm 44 about the movable axis 45. The cam member 46 has a fiat surface 49 cooperating with the fiat surface 48 of the support frame 26 and a true, partial circular surface 50 cooperating with an adjacent flat surface 51 of the insulator 40 whereby when the cam member 46 is disposed in a position having the flat surface 49 disposed against the flat surface 48 of the frame 26, the elements 40, 42, 33, 39, 34, 43 and 41 are disposed in stacked relation between the opposed ends 30 and 31 of the support frame 26 and will not alter the stresses in the crystal elements 33 and 34 to generate a potential difierence at the respective terminal means 35, 36 and 37, 38 until the cam element 46 is rotated about the axis 45 to either axially squeeze the elements 33 and 34 between the opposed ends thereof or relieve such squeezing action.

In particular, when the rocker arm 44 is rotated in a counterclockwise direction in a manner hereinafter described, the cam element 46 will rotate about its axis 45 in a counterclockwise direction so that the corner 52, formed by the juncture of the fiat surface 49 thereof and the circular surface 50 thereof, will bear against the flat surface 48 of the support frame 26 and cause the axis 45 to move upwardly and to the right in FIG. 2 to increase the effective length of the cam member 46 between the surface 48 of the support frame 26 and the surface 51 of the insulator 40 to impose a substantially longitudinal compressive and squeezing action on the elements 33 and 34 between the ends 30 and 31 of the support frame 26 so that the stresses in the crystals 33 and 34 are sufiiciently altered to cause the same to create a potential dillerence at the respective pairs of terminals 35, 36 and 37, 38 to be utilized in a manner hereinafter described. When such compression or squeezing action on the crystal means 33 and 34 are subsequently relieved by the rocker arm 44 moving in clockwise direction in FIG. 2 to place the flat surface 49 of the cam 46 against the flat surface 48 of the frame 26, the cam member 46 will effectively decrease the effective cam length of the cam member 46 between the surfaces 48 and 51 to thereby again alter the stresses in the crystal elements 33 and 34 as the same longitudinally expand from their previous squeezed condition to also generate a potential difference at the respective pairs of terminals 35, 36 and 37, 38.

During such rotation of the cam element 46, the stack of elements 40, 42, 33, 39, 34, 43 and 41 tends to rock as a unit to the right as the cam element 46 is rotated in a counterclockwise direction and tends to rock to the left when the cam element 46 is rotated in a clockwise direction back to the non-squeezing position whereby the insulator 41 can be provided with an arcuate surface 53 Cit that bears against a fiat surface 54 of the support frame 26 to permit such rocking of the stack of elements between the opposed ends 30 and 31 of the support frame 26.

A first pair of electrodes 55 and 56 are mounted to the frame means 27 of the apparatus 10 adjacent the respective pilot burners 21 and 22 and in spaced relation from the pilot burners 21 and 22 so as to define spark gaps 57 and 58 adjacent the fuel outlet means 59 and 60 of the pilot burners 21 and 22. The electrodes 55 and 56 are electrically insulated from the frame means 27 of the apparatus 10 and are electrically interconnected to the teminals 35 and 36 by suitable leads 61 and 62.

Similarly, another pair of electrodes 63 and 64 are carried by the apparatus 10 and are disposed in spaced relation from the pilot burners 19 and 20 to define spark gaps 65 and 66 adjacent the fuel outlet ends 67 and 68 of the respective pilot burner means 19 and 20. The electrodes '63 and 64 are also electrically insulated from the frame means 27 of the apparatus 10 and are respectively interconnected to the terminal means 37 and 38 by leads 69 and 70.

The pilot burner means 21, 22, 19 and 20 are electrically conductive and are, in effect, connected to a ground potential by being electrically interconnected to the frame means 27 of the apparatus 10 and such ground potential of the pilot burners is generally indicated by the reference numerals 71 and 72 in FIG. 2, the frame means 27 of the apparatus 10 being effectively grounded through interconnection thereof to the gas supply lines and the like and also by conventional grounding means.

In this manner, it can be seen that the pilot burner means 21 and 22 respectively provide ground electrodes cooperating with the electrodes 55 and 56 to define the spark gaps 57 and 58. Similarly, the pilot burners 19 and 20 provide ground electrodes for cooperating with the electrodes 63 and 64 to provide the spark gaps 65 and 66.

The operation of the igniting means 25 for the apparatus 10 will now be described.

When the housewife or the like notices that one of the burner means 12, 13, 15, 16, 17 or 18 does not ignite when she turns on one of the main selector knobs of the apparatus 10, or when she actually notices that one of the pilot burner means 19, 20, 21 and 22 are not burning, she can merely turn on the manual actuator means 28 to effect rocking of the cam member 46 of the igniter means 25 whereby the stresses in each crystal element 33 and 34 will be altered in the manner previously described so that one potential will be created at the electrodes 55 and 63 and an equal and opposite potential will be created at the electrodes 56 and 64. When the differences in potential between the electrodes 55, 56, 63 and 64 and their respective grounded electrodes 21, 22, 19 and 20 reaches a particular magnitude, electrical arcing will be created across the spark gaps 57, 58, '65 and 66 in substantially a simultaneous manner whereby such electrical sparking will ignite the fuel issuing from any unlit pilot burner means 21, 22, 19 or 20.

Continued operation of the manual actuator means 28 will effect a continuous cycling movement of the rocker arm 44 to first provide a squeezing action on the elements 33 and 34 to produce the above-described sparking one or more times depending upon the length of counterclockwise movement of the rocker arm 44 and then provide a relieving of the compression force on the elements 33 and 34 by the subsequent clockwise movement of the rocker arm 44 that also alters the stresses in the crystals 33 and 34 to effect sparking at the spark gaps 5 7, 58, 65 and 66.

This continuous cycling movement of the rocker arm 44 in its counterclockwise and clockwise directions to cause the aforementioned sparking at the spark gaps 57, 58, 63 and 66 is produced as long as the housewife or the like causes the manual actuator means 28 to interconnect a pneumatic source 73 to apneumatically operated actuator means 74 of this invention. the manual actuator means 28 being illustrated in FIG. 2 as a valve member disposed in a conduit means 75 leading from the pneumatic source 73 to the actuator 74 and the source 73 comprising a vacuum pump.

The pneumatically operated actuator means 74 of this invention comprises a housing means 76 formed by two cup-shaped housing members 77 and 78 snap fitted together at their open ends 79 and 80 to not only secure the housing members 77 and 78 together but also to sealing trap and secure an outer peripheral edge means 81 of a flexible diaphragm 82 therebetween, the flexible diaphragm 82 cooperating with the cup-shaped housing member 76 to define a chamber '83 therebetween.

The flexible diaphragm 82 has its inner periphery 84 snap fitted into an annular recess 85 of an actuating post 86 that has an integral diaphragm backup plate means 87 on one end thereof inside the chamber 83 and an elongated stem part 88 at the other end thereof that projects through an opening means 89 in the end wall 90 of the cup-shaped housing member 78 to be pivotally intercom nected to the right hand end 91 of the rocker arm 44. For example, the end 91 of the rocker arm 44 can be received in a slot 92 at the free end of the stem 88 and be pivotally interconnected thereto by a pivot pin 93 carried by the stem 88 and passing through an elongated slot 94 in the end 91 of the rocker arm 44.

The end wall 95 of the other cup-shaped housing member 77 is interrupted by a plurality of first passage means 96 disposed in a concentric manner about a second passage means 97 passing centrally through the end wall 95, the passage means 96 and 97 respectively leading to the chamber 83 of the actuator 74. An adaptor 98 is carried by the housing means 76 and is disposed in sealing relation against the exterior surface of the end wall 95 of the cup-shaped housing member 77 as illustrated in FIG. 2, the adaptor 98 having a first tubular nipple means 99 provided with a passage 100 that is disposed in fluid communication with the first passage means 96 and is adapted to be fluidly interconnected to the conduit means 75, such as by having the conduit means 75 telescopically disposed over the nipple 99'. In this manner, the selector valve means 28 is disposed intermediate the pneumatic source 73 and the first passage means 96 of the actuator 74 for a purpose hereinafter described.

The adaptor 98 carries another tubular nipple means 101 having a passage 102 provided therein that defines a chamber 103 in fluid communication with the second passage means 97 of the actuator 74. In this manner, the passage 102 can be interconnected to the atmosphere for a purpose hereinafter described by a suitable conduit means telescoped on the nipple 101 and carrying suitable filter means (not shown) to filter air that will enter into the chamber 83 from the passage means 102 in a manner hereinafter described.

The actuator 74 carries a valve means generally indicated by the reference numeral 104 for controlling the passage means 96 and 97, the valve means 104 comprising a first valve part 105 for controlling the passage means 96 and a second valve part 106 for controlling the passage means 97.

The valve part 105 is in substantially disc shape form and has an annular groove 107 therein which defines two annular valve seating surfaces 108 and 109 so constructed and arranged that when the same seat against the undersurface 110 of the end Wall 95 of the housing member 77, such groove 107 is in fiuid communication with the first passage means 96 so as to completely close the passage means 96 from the chamber 83. The first valve part 105 also has a plurality of opening means 111 passing therethrough inboard of the annular seating surface 109 and outboard of a central opening 112 passing therethrough and receiving a stem 113 projecting from the valve part 106 and extending through the central opening 97 in the end wall 95. The stem 113 of the second valve part 106 also has a shoulder means 114 adapted to abut against the first valve part 105.

The second valve part 106 of the valve means 104 has an annular seating surface 115 for seating against the external side 11-6 of the end wall so as to close the passage means 97 from the chamber 83.

A first compression spring means 117 is disposed in the chamber 83 and has one end 118 disposed against the backup plate 87 of the diaphragm 82 while the other end 119 thereof is disposed against the valve part 105 and tends to urge the valve part 105 toward its closed position. A second compression spring 120 is carried by the actuator 74 and has one end 121 abutting against the adaptor 98 and the other end 122 abutting the second valve part 106 to tend to cause the valve part 106 to close the passage means 97.

The operation of the actuator means 74 of this invention for providing a continuous squeezing and relieving cycling action of the igniter means 25 will now be described.

Normally the valve means 28 is disposed in a position to prevent the vacuum source 73 from being interconnected to the passage of the nipple 99 so that the actuator 74 is normally disposed in the position of FIG. 4 where the chamber 83 is at atmospheric condition and the diaphragm 82 and actuating post means 86 are in their outermost'deactuated stroke position, such position of the actuator 74 being coordinated with the igniter means 25 to maintain the rocker arm 44 so that the cam member 46 has its flat surface 49 disposed flat against the flat end surface 48 of the support frame 26.

However, when the housewife or the like desires to initiate an igniting cycle, the housewife or the like turns on the selector or manual actuator means 28 to a position thereof which will interconnect the vacuum source 73 with the nipple 99 of the actuator 74 and as long as the selector means 28 maintains such fluid communication, the actuator 74 will cause continuous cycling action of the rocker arm 44 as previously described.

In particular, with the vacuum source 73 now interconnected to the chamber 83 when the actuator 74 is in the position of FIG. 4, it can be seen that the compression spring 117 is in its extended condition so that the force of the compression spring 120 is sufiicient to maintain the second valve part 106 in its closed position against the end wall 95 to prevent fluid communication of the chamber 83 with the atmosphere while the shoulder means 114 thereof maintains the first valve part away from the end Wall 95 to permit fluid communication between the passage means 96 and the chamber 83. Thus, as the chamber 83 is being evacuated by the interconnected vacuum source 73, the pressure diiferential across the diaphragm 82 causes the diaphragm 82 to be pulled upwardly in the manner illustrated in FIG. 2 to cause counterclockwise rotation of the rocker arm 44 for the previously described sqeezing action on the crystal means 33 and 34 for sparking at the spark gaps 57, 58, 65 and 66 in the manner previously described.

As the diaphragm 82 is being drawn upwardly by the continued evacuation of the chamber 83, the compression spring 117 is being progressively compressed between the backup plate 87 and the valve part 105 that is maintained away from the end wall 95 by the combined effect of the compression spring and the pressure difi'erential acting on the valve part 106 that maintains the valve part 106 at its closed position.

However, when the diaphragm 82 reaches the position illustrated in FIG. 2, it can be seen that the backup plate 87 of the diaphragm 82 contacts the end of the stem 113 of the valve part 106 to cause the valve part 106 to move upwardly in unison therewith so that not only is the passage means 97 now opened by the upwardly moving diaphragm 82, but also the valve part 105 can now move upwardly with the diaphragm 82 and seat against the end wall 95 to disconnect the vacuum source 73 from the chamber 83.

At this time, the diaphragm and actuating post 86 have reached their predetermined actuated position and have caused the beginning of the deactuation cycle of the actuator 74.

In particular, with the valve part 106 now in its open position in the manner illustrated in FIG. 3, atmosphere can return through the nipple means 101 into the chamber 83 and thereby permit the compression spring 117 to begin to move the diaphragm 82 and actuating post 86 from substantially the position illustrated in FIG. 2 toward the position illustrated in FIG. 3. During such downward movement of the diaphragm 82, even though the force of the compression spring 117 is progressively decreasing, the valve part 106 is maintained in its opened position in opposition to the force of the compression spring 120 because of the pressure differential acting on the valve part 105 to maintain the same in its closed position against the end wall 95 because the vacuum source 73 is still in fluid communication with the annular groove 107 of the valve part 105.

During such deactuation of the actuator 74, it; can be seen that the rocker arm 44 is now being moved in its clockwise direction to relieve the previously squeezed condition of the crystal means 33 and 34 to further cause sparking at the spark gaps 57, 58, 60, 65 and 66 in the manner previously described.

When the diaphragm 82 and actuating post 86 reach their predetermined deactuated stoke position as illustrated in FIG. 4, the force of the compression spring 117 has so decreased that the force of the compression spring 120 can now overcome the combined force of the compression spring 117 and the pressure differential acting on the valve part 105 to move the same downwardly to the position illustrated in FIG. 4 whereby the valve part 106 will now close the passage means 97 so that the chamber 83 is no longer interconnected to the atmosphere and the vacuum source 73 will again be interconnected to the chamber 83 to begin an actuation stroke of the actuator 74.

Therefore, it can be seen that as long as the vacuum source 73 is being interconnected to the nipple 99 of the actuator 74, the actuator 74 Will automatically cycle between its actuated position and deactuated position to cause rocking of the rocker arm 44 in a cycling manner so as to continuously create sparking at the spark gaps 57, 58, 65 and 66 to insure full ignition of the pilot burner means 19-22.

While the selector or manual actuator 28 has been previously described as being a valve means that must be held in a certain position by the housewife to maintain continuous interconnection of the vacuum source 73 with the actuator 74, it is to be understood that the selector means 28 could be a timer arrangement so that when the housewife or the like initiates an ignition cycle by manually actuating the actuator 28, the actuator 28 will maintain full communication of the vacuum source 73 with the actuator 74 for a predetermined time period after the lapse of which the selector means 28 will automatically disconnect the vacuum source 73 from the actuator 74 until the selector means 28 is again actuated by the housewife or the like.

While the actuator 74 of this invention has been previously described and illustrated as actuating a particular piezoelectric crystal means 25 disclosed and claimed in the aforementioned copending patent application, it is to be understood that such actuator means 74 could be utilized to operate another type of pizoelectric crystal means for ignition purposes as well as operate other devices unrelated to ignition means.

Therefore, not only does this invention provide an improved pneumatically operated ignition means for a cooking apparatus or the like, but also this invention provides an improved pneumatically operated actuator means.

While the form of the invention now preferred has been disclosed as required by the statutes, other forms may be used, all coming within the scope of the claims which follow.

What is claimed is:

1. In combination, a vacuum operated actuator, a vacuum source, interconnection means for interconnecting said source to said actuator, and a piezoelectric crystal ignition means for burner means or the like, said actuator being operatively interconnected to said ignition means to alter the stresses therein at least during one of the actuation and deactuation strokes thereof, said actuator having means for automatically causing said vacuum source to actuate the same to a predetermined actuated stroke position and thereafter deactuating the same to a predetermined deactuated stroke position thereof in a continuous cycling manner as long as said source is interconnected to said actuator.

2. A combination as set forth in claim 1 wherein said interconnection means interconnecting said source to said actuator comprises a passage defining means having a selector valve means for selectively opening and closing said passage defining means.

3. A combination as set forth in claim 1 wherein said ignition means is of the squeeze-type whereby the stresses thereof are altered on both the actuation and deactuation strokes of said actuator.

4. A combination as set forth in claim 3 wherein said ignition means has a movable lever for causing the squeeze action thereof, said lever being interconnected to said actuator.

5. A combination as set forth in claim 1 wherein said actuator has a chamber therein defined in part by a movable wall of said actuator, said actuator having first passage means leading to said chamber and being interconnected to said source by said interconnection means, said actuator having second passage .rneans leading to said chamber and being interconnected to the atmosphere, said automatic means of said actuator comprising valve means for controlling said first and second passage means.

6. A combination as set forth in claim 5 wherein said valve means comprises first and second valve parts respectively controlling said first and second pasage means.

7. A combination as set forth in claim 6 wherein a first spring means is disposed between said movable wall of said actuator and said first valve part to tend to urge said first valve part to close said first passage means.

8. A combination as set forth in claim 7 wherein a. second spring means is carried by said actuator and tends to urge said second valve part to close said second passage means.

9. 'In combination, a pneumatically operated actuator, a pneumatic source, interconnection means for interconnecting said source to said actuator, a piezoelectric crystal ignition means for burner means or the like, said actuator being operatively interconnected to said ignition means to alter the stresses therein at least during one of the actua tion and deactuation strokes thereof, said actuator having means for automatically causing said pneumatic source to actuate the same to a predetermined actuated stroke position and thereafter deactuating the same to a predetermined deactuated stroke position thereof in a continuous cycling manner as long as said source is interconnected to said actuator, said actuator having a chamber therein defined in part by a movable wall of said actuator, said actuator having first passage means leading to said chamber and being interconnected to said source by said interconnection means, said actuator having second passage means leading to said chamber and being interconnected to the atmosphere, said automatic means of said actuator comprising valve means for controlling said first and second passage means, said valve means comprising first and second valve parts respectively controlling said first and second passage means, a first spring means being disposed between said movable wall of said actuator and said first valve part to tend to urge said first valve part to close said first passage means, and a second spring means being carried by said actuator and tending to urge said second valve part to close said second passage means, said pneumatic source being a vacuum source for imposing a vacuum in said chamber through said first passage means and moving said movable wall toward its predetermined actuated stroke position in opposition to said first spring means, said chamber when returning to atmospheric condition 'by said second passage means causing said first spring means to move said movable wall toward its predetermined deactuated stroke position.

10. In combination, a pneumatically operated actuator, a pneumatic source, interconnection means for interconnecting said source to said actuator, a piezoelectric crystal ignition means for burner means or the like, said actuator being operatively interconnected to said ignition means to alter the stresses therein at least during one of the actuation and deactuation strokes thereof, said actuator having means for automatically causing said pneumatic source to actuate the same to a predetermined actuated stroke position and thereafter deactuating the same to a predetermined deactuated stroke position thereof in a continuous cycling manner as long as said source is interconnected to said actuator, said actuator having a chamber therein defined in part by a movable wall of said actuator, said actuator having first passage means leading to said chamber and being interconnected to said source by said interconnection means, saidactuator having second passage means leading to said chamber and being interconnected to the atmosphere, said automatic means of said actuator comprising valve means for controlling said first and second passage means, said valve means comprising first and second valve parts respectively controlling said first and second passage means, a first spring means being disposed between said movable wall of said actuator and said first valve part to tend to urge said first valve part to close said first passage means, and a second spring means being carried by said actuator and tending to urge said second valve part to close said second passage means, said spring means being so constructed and arranged that said second spring maintains said second valve part in its closed position until said movable wall reaches its predetermined actuated stroke position and engages and moves said second valve part to its open position in opposition to the force of said second spring means, said valve parts being operatively interconnected together so that when said second valve part is moved to its open position by said wall said first valve part can move to its closed position and will remain in its closed position until said wall moves to its predetermined deactuated stroke position where said spring means cause said first valve part to move to its open position and said second valve part to move to its closed position.

References Cited UNITED STATES PATENTS 3,136,355 6/1964 Weber 431-6 3,172,456 3/1965 Glasgow 431255 3,336,945 8/1967 Bostock l37---624.14 3,344,835 10/1967 Hodgson 431-255 3,345,915 10/1967 Dotto l37----624.14 3,354,327 11/1967 Benson 3109.1,

MILTON O. HIRSHFIELD, Primary Examiner M. O. BUDD, Assistant Examiner US. Cl. X.R. 

